The present invention relates to a new and improved construction of a marine vessel containing at least one vessel propeller.
Generally speaking, the marine vessel of the present development is of the type wherein the aforementioned at least one propeller is located essentially over one-half of its circumference within a tunnel formed at the floor or bottom of the hull or body of the vessel. The tunnel possesses a flow-favorable transitional shape which follows the flow lines of the water and which transitional shape is developed at the region of the floor of the vessel. At the transition region between the surface of the vessel floor and the tunnel there is arranged a retractable and extendable control plate which is pivotably mounted at the hull or body of the vessel and merges with the floor surface of such vessel.
Such type of marine vessel has been disclosed in the aforementioned copending U.S. application Ser. No. 06/191,381 and the cognate German Patent application No. 30 05 682.7. With such design of marine vessel the control plate is pivotably connected in a hinge-like fashion at a shaft arranged transversely with respect to the direction of travel of the marine vessel and can be positionally adjusted by means of a piston-and-cylinder mechanism between a retracted position, where the control plate bears against the surface of the tunnel, and an extended position remote from such tunnel surface. With such arrangement there can arise at the transition location between the vessel floor and the control plate at both of these parts damage because of cavitation erosion. Furthermore, the transition location can become contaminated by foreign bodies or particles, and thus, can impair the mobility and functional reliability of the control plate.